@desolutionist See my rule proposal directly above your reply:
RESTRICT: Cards that are non-permanents that causes you to draw and net 2 or more cards than mana spent to cast, through any method of casting via the card itself, in the same turn.
This hits Cruise, but not Dig. Delve is a method of casting. Ancestral Visions can't be cast at all via the card itself (only suspended), so it would remain unrestricted. The suspended casting would fail the "in the same turn" caveot (maybe a tweak in wording could clarify that).
Dig could perhaps be lumped in with "tutor" or "card selection" cards via a different rule. Making these rules should not be quick and easy. They need to be deliberate and thought out and ratified, much like constitutional amendments.